The present invention relates generally to a stereo imager, and more particularly to a stereo imager capable of taking stereo images on a small-format and single image pickup device.
A camera capable of real-time taking two images having parallaxes juxtaposed in the left-and-right direction for the same subject has so far been known in the art. Since an oblong image pickup plane is usually used for taking, it is general that two images are arranged side by side in the left-and-right direction. However, when it is desired to obtain horizontally long stereo images with such a taking arrangement, two horizontally long images must be arranged in the horizontal direction, resulting in a useless space on the image pickup plane. For instance, when two such images are simultaneously picked up by means of a single image pickup device for range finding or the like, it is difficult to obtain detailed image information.
To solve such a problem, patent publication 1 comes up with a stereo taking optical system for capturing stereo images on an oblong image pickup plane in the vertical direction.
In this optical system, a film plane is vertically divided into upper and lower areas, as shown in FIGS. 1 and 2 of patent publication 1, and left and right images having parallaxes are guided to the upper and lower areas of the film plane by ways of two reflecting surfaces for each.
Patent Publication 1
JP(A)8-171151
However, the taking optical system or the like set forth in patent publication 1 comprises optical systems having at least two different entrance positions, and so is not preferable because control of each optical system requires more members and variations are likely to occur from optical system to optical system.
With such problems with the prior art as described above in mind, one object of the invention is to provide a stereo imager that is reduced in the number of members, favorable in view of cost and less susceptible to variations from optical system to optical system.